Metal-shears.



No. 879,900. PATENTED FEB.'25, 1908. G. POTSTADA.

METAL SHEARS.

APPLICATION FILED OOT.22,1907.

I UNITED STATES PATEnT OFFICE.

GEORGE POTSTADA, OF SAN FRANCISCO, CALIFORNIA.

- METAL-SEARS.

Specification of Letters Patent. Application filed October 22.1907 Serial No; 398.673-

Patented Feb. 25, 1908.

To allwhom it may concern: Be it known that I, GEORGE POTSTADA, a subject. of the Emperor of Germany, residing at San Francisco, in the county of San Francisco and State of California, have invented a new and useful Metal-Shears, of which the following is a specification in such full and clearlte'rms as will enable those skilled in the art to construct and use the same.

, This invention relates to shears used for the purpose of cutting sheet metal of any desiredthickness up to about three eighths of an inch, the principal object of the invention being to make the cutting of the metal much easier than with the plain shears commonly called plumbers sni s Another object of t 1e invention is to make a pair of shears that will cut the sheet metal without having the same curl up beside the hand of the person using the shears, and to make iteasy to cut a hole out of the center 'of a sheet of material which would be impossible to cut with the snips.

A further object of the invention is to provide means whereby the metal cut out wi lbe led from the cutter in such a way as not to interfere with the proper working of the shears. i

.- In the drawings, in which the same numerals areapplied to the same parts throughout, Figure 1 is an end elevation of the shears looking at the handle end; Fig. 2 is a side elevation of the shears, the handles being cut short; Fig. 3 is a plan of the shears, Fig. 4 is a side elevation of the handle alone, the handle head being shown in section, Fig. 5 is a front elevation pf the shears, Fig. 6 is a front edge view of-tliekiiife, Fig. 7 is a front view of a modified form of the shears, Fig. is a side elevation of the modification, and Fig. 9 is a frontview of a removable knife that may be used, if desired, with either form of the shears. I

The shears are made from any suitable vide means to releasethe cutting knife from 'metal is being cut by theknife 5.

material, as sheet steel, steel plate, or cast steel. The handles are'made of any material that is stiff enough to give the necessary strength, the handle 1 carrying a head 7 and the handle 2 being secured to the plates 3 of the shears. The head of the shearsis made of two plates 3, 3 which are riveted to the handle 2 by any desired number of rivets, it being understood that to resist the strains put on it that .the riveting must be very strong. -The plates 3 have eyes 4 near the top thereof and another rivet 1S placed in the plates in front of the knife to keep the plates from being pushed apart when a sheet of x The 7 knife 5 is L- shaped, as indicated by the dotted lines in Fig. 1, and itis carried b the pin 6 which passes eccentrically throw the head 7 of the handle 1. Now it will be observed that any motion of the head 7 will cause the knifeto move up or down, as'the case may be, and that it will cut from a sheet of metal a strip ofthe same width as the space between the'plates 3, but since this strip is not ver f wide it isnot much of a loss. It will be note that the knife has its cutting edge inclined from the right downwardly, see Figsf5 and 6. The object of having the knife inclined in this way is to cause the strip out out to curl up in a spiral at one side of 35 the shears, since if the knife is square across thestrip will curl up straight in front of the knife and make it very difficult to finish the cut.

It will be observed that the plates 3 are n wider apart a short distance above the lower edge than at said edge, the object of this being to release the out out strip easily and not become clogged with the metal cut out. Itwill be noted that the knife has a narrow 5 shank just above the cutting edge at 10, and that it ta ers below said edge, the purpose of each. 0 these narrow parts is to make it easier to move the knife in the cut. The knife is pulled up through a sheet of metal to 00 the position indicated by the full lines in Fig. 1 when the entire out has been made,

' now if the knife is the same size to its'lower so it has the narrow shank '10 to enable it to be pushed ahead easily, when opened for a second, out. When the knife has pushed through the metal on one cut the two sheets of metal spring back ver strongly andif no means is provided to pus the knife throu the metal it is very liable to move the s I ars up instead. of moving back through the metal for another cut, so to make sure that the knifeis pushed back for another out the guide plate 11 is provided with two lugs l2jwhich extend across thecut and keep the sheet of metal up close to the bottom of the plates 11.3 when the knife is being pushed down by the movement of the eccentrically placed pivot in the handle head 7. This part 11 also acts to'guide the cut straight ahead, but since it is often necessary to out a short curve it is pivoted in the plates 3, a spring-13 securedto the handle 2 serving to hold the guide in either the operative or the inoperative position.

Modifications of the invention may be madewithout departing from the spirit thereof and one such modification is shown in Figs. 7 and 8. In this form of the invention the knife moves down on the cutting stroke instead of up as in the other figures, and it 'is carried by plate 20 which is bent around into a U shape, said plate 20 being riveted to the bar 21 and to the handle 22. Near the top of the late are the eyes 24, 24 in which is carried tl ie head 25 of the handle 26. This head 25 is provided with an eccentric, pivot pin the same as that shown for the other form of the invention, and pivoted on this in 27 is the knife 28. The parts for the e to operate against are the )lates 29 which are riveted to the bar 21. t will be observed that the plate 24 acts as the lugs 12 do in the other form of the invention since this knife is pulling out of the cut on the upward stroke. It will be observed that the ,plates 3, 3 in the first form of the invention are widened'at 8 and 9 and the plates 29 in the modification are widened in the same way in order to allow the stri) of cut metal to be taken out of the slot easily. The knife in each case is a little thicker at the upper part than at the cutting edge in order toincrease the bearing surface at that point, note Fig. 6.

If the head is made from a casting it will be necessary to provide means to make the edge of the casting stand up under the strains due to cutting and this-is done by letting into the plate 3 see Fig. 9, the'steel plate 30 which is held in place by means of air of screws or rivets.

aving thus described my invention What I claim as new and wish so secure by Letters Patent of the United States is as fpllows:

1. In a metal shears, the combination with a pair of handles, of a knife carried by one of the handles, a head carried by the other been a cut is made. i

3. In a metal shears, the combmat on with a pair of handles, of a knife carried by elongated shank passingl through it carried by said handle,a ead earned by the other handle and through which the knife is adapted to slide, and a guide in the rear of the knife to keep the out straight.

4. In a metal shears, the comb'ilation'of a head having a handle secured thereto said {head comprlsed of a pair of plates having cir- "cular eyes near the top thereof, a head fitted to said eyes'and having a handle secured thereto, a in in said head and eccentrieally placed wit respect to the head, a knife carried by the head and having a cutting edge at substantially a right angle with the shank, and means inthe rear'of the knife to guide the shears as the cut in the metal is made.

head having a handle secured thereto said head having a pair of circular eyes near. the top thereof, a second handle having ahead to fit said eyes and having a pin placed eccentricallyv with reference to sald eyes and head, a knife carried by'the pin and having its cutting edge extending at right angles with its supporting shank theshank of said knife just above the cutting edge being thinner than the cutting edge, a guide carried by the shear head and having lugs on each side thereof whereby the sheet'is held close to the shears when the knife is pushed against the sheet on the inoperative stroke. 6. In a metal shears, the combination of a head carried by a handle and having a pair fitting said eyes and having a handle, ,a in placed eccentrically of said second head; a

nife carried by said pin and having its cutting edge at substantially a right angle with its shank said cutting edge also being at an angle other than 90 degrees with the line of motion of said knife, and a hinged guide carried by the shear head.

head carried. by'a handle said head having a. pair of e es near the to thereof, a second andled ead fitting sai eyes and having a pin placed eccentrically of said head, a nife carried by said second head, a ivoted guide carried by the first head and p seed in guide the shears across the metal sheet, as the a one of the handles said knife having ea of eyes near the top thereof, a second head 5. In a metal shears, the combination of a V 7. In a metal shears, the combination of a the ffeafi of tha knifeffind a spring adapted to I head and in the rear of the kiife, and a 1 splrng hol t e gui e in t e operative or the ini bearing on the guide and a apted to o it 15 operative position. f in the operative or the inoperative position 8. In a metal shears, the combination of a l at the Will of the user. i handle carrying a head having a pair of eyes In testimony whereof I have set my Hand near the top thereof,- a second handle carryin the presence of the two subscribed Witing a head fitting said eyhes 1and having a pin nesses. placed eccentrically of t e ead a knife car- I l i ried by the head in the eyes said knife being I GEORGE POTSTADA' l0 thinner above the cutting edge than at said Witnesses:

edge said cutting edge also being inclined at l W. T. Hnss,

an acute angle to the line of motion of said d C. P. GRIFFIN. knife, a pivoted guide carried by the shear j 

